1. Field of the Invention
The present invention relates to a semiconductor device. In particular, the present invention relates to a semiconductor device capable of communicating data wirelessly, a so-called IC chip (also referred to as an ID chip and a transponder) for RFID (radio frequency identification).
Note that the semiconductor device herein refers to all devices which can function by utilizing the semiconductor characteristics.
2. Description of the Related Art
In recent years, environment where it is possible to access an information network anytime and anywhere, which is called ubiquitous information society, has been developed. In such environment, an individual identification technique in which an ID (individual identification number) is given to an individual object to clarify records of the object so that it is useful for production, management, and the like has been developed for practical use. In particular, semiconductor devices which utilize an RFID (radio frequency identification) technique and perform wireless data communication with external communication devices (hereinafter referred to as communication devices, and also referred to as reader/writers, controllers, and interrogators) have been widely spread and put into practical use. Such semiconductor devices are hereinafter simply referred to as semiconductor devices and also referred to as ID chips, IC chips, and transponders.
In order to promote the spread of the semiconductor device, it is important to improve the reliability of the semiconductor device. Patent Document 1 (Japanese Published Patent Application No. 2002-83277) discloses a structure in which a semiconductor device including one antenna is provided with two semiconductor integrated circuits in order to improve the reliability of the semiconductor device.